The row over Lord Ashcroft, the billionaire Conservative donor, threatens to cause David Cameron more damage.

Yet the issue of donations by non-doms — people non-domiciled for tax purposes — should be straightforward. No party should accept donations from anyone not prepared to pay UK tax on overseas earnings.

The problem affects Labour too: today the billionaire steel magnate and Labour donor Lord Paul has conceded in an interview with the New Statesman that he will pay tax from April. That is because he will be forced to do so by a change in the law that will prevent non-doms sitting in Parliament. Lord Ashcroft's case is more serious.

First, he has continued to maintain his non-dom status despite pledging to become a permanent resident — he spends a lot of time in Belize — when awarded a peerage 10 years ago. Second and more important, he is a far more integral part of the Tory machine than any donors are of Labour's: he is the party's deputy chairman and a former treasurer, while he has given it around £4 million, much of it targeted at campaigns in marginal seats.

Today Tory grandee Lord Kalms has slammed Mr Cameron, saying that he and shadow foreign secretary William Hague should have been "more alert" to the problem. He has also been critical of Lord Ashcroft, telling the Standard that the peer's non-dom status goes against "the spirit of the party". Lord Kalms is right. Wealthy individuals should not expect to be able to donate without paying tax like those parties' voters — and Mr Cameron should make that clear to Lord Ashcroft.

Canine menace

Today's initiative to tackle dangerous dogs, announced by Home Secretary Alan Johnson, is a belated recognition of a real problem, especially in London. Fierce dogs have become steadily more visible on our streets and the number of injuries caused by them is rising. Sadly, the Government's approach is unrealistic.

Mr Johnson's proposals would give police and councils powers to issue "dog control notices", as well as requiring dog owners to microchip their animals and have third-party insurance for any injuries the dog causes. Such restrictions would be a costly burden on law-abiding citizens, while those people who own dangerous dogs and use them to threaten others are unlikely to bother with niceties such as the correct insurance cover.

The Dangerous Dogs Act 1991 is a flawed piece of legislation, proscribing just four breeds from public places. It needs expanding: there is no reason why anyone should be allowed to own such dogs at all, any more than they are allowed firearms. Police and council officers need powers to confiscate and destroy any dangerous dog more easily.

The real challenge, though, will be getting police to take the problem seriously and to go in hard enough against the criminals responsible for breeding and using such dogs. Today we report that the Metropolitan Police's dedicated dogs unit is set to seize 1,000 dogs in its first year of operation — a welcome if belated response to the problem. Until police take a harder line, new laws are unlikely to achieve much.

Eye on London

The London Eye is 10 years old today and in that time has become an institution. The 135m-high wheel is now part of the capital's skyline and the view of the Thames, while 36 million Londoners and visitors alike have marvelled at its vast views over our city. The Eye's owners say today they expect it to go on into the 22nd century. We hope so.